48 
MANURES. 
alkalies and porous bodies compel the constituents of 
air, under certain circumstances, to unite and form 
aqua-fortis, and this immediately unites to the alkali, 
and forms saltpetre. The best alkali to compel this 
union, is ammonia. Hence, where plenty of animal 
matter is fermenting, or rotting, or where plenty of 
urine is, there, porous bodies being present, saltpetre 
will be formed. Now this is enough for you, to un¬ 
derstand the principle upon which I propose to you to 
form an artificial nitre bed for your own use. It has 
been found that the manure of twenty-five cows, asses, 
and mules, in layers of about four inches thick, with 
layers of the same thickness of chalky soil, first one 
and then the other, and now and then damped with 
the urine of the stable, produces from 1,000 to 1,200 
lbs. of saltpetre in four years. 
The heap is formed under cover, and occasionally 
shovelled over. At the end of two years, it is a mass 
of rich mould. It is left two years longer, with an 
occasional turning over, but it is not wet with urine 
for the last few months. The dung the farmer has 
always; he wants the porous chalky body. This may 
be furnished by spent ashes, mixed up with its bulk 
of loam. Hence the following rule may be given :— 
One cord of clear cow dung, one cord of spent ashes, 
one cord of loam or swamp muck. Mix the ashes and 
the swamp muck well, and having hard rammed the 
barn cellar floor, or that under a shed, lay a bed upon 
it four inches thick, of these mixed materials; then a 
layer of dung, three or four inches thick, and so on, 
till the pile is two or three feet high, topping off with 
loam. Wet it occasionally with urine, keeping it 
always about as moist as garden mould. Shovel over 
once a fortnight for two years. The pile now contains 
about fifty pounds of several varieties of saltpetre, and 
mixed throughout with nearly three cords of excellent 
manure. It may, therefore, be now used, according 
to the farmer’s judgment. By thoughtful manage¬ 
ment, he may, after the first two years, annually col- 
